1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)

1.3 Conditions regarding the use of data documented through WOCAT

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

Yes

1.4 Declaration on sustainability of the described Technology

Is the Technology described here problematic with regard to land degradation, so that it cannot be declared a sustainable land management technology?

No

2.1 Short description of the Technology

Definition of the Technology:

Gully rehabilitation by check dams made of stem cuttings from trees. These living barriers retard concentrated runoff and fill up the gullies gradually with sediment.

2.2 Detailed description of the Technology

Description:

Stem cuttings from specific tree species have the ability to strike roots and continue growing after being planted into the earth. In this case study local species have been used to create check dams in gullies: these include jinocuebo (Simaroubaceaes bombacaceaes, and also jobo, tiguilote, pochote from the same family). Other suitable species are jocote (Spondias purpurea) and madero negro (Gliricidia sepium). As an option the pinapple-like piñuela (Bromelia pinguin) can be planted in association with the stem cuttings to further reinforce the system. Tree stems are cut into pieces 5-15 cm thick and 1.5-2.5 m long, depending on the depth of the gully. The cuttings are planted to half of their length, and formed into semi-circular barriers (see diagram). The dams retard runoff and thus retain eroded sediment. Spacing between dams depends on the gradient of the gully bed. For example on a 15% slope it is recommended to build a dam every 4 meters (see spacing under establishment activities). Between dams, the gully gradually fills up with eroded soil, the speed of the runoff is further reduced and agricultural land that has been divided by the gully is reconnected. Large and deep gullies may change over time into a sequence of narrow fertile terraces where crops can be grown.

However, the check dams should be seen as part of an integrated catchment management and protection plan, and thus be supported by other SWC measures on the lateral slopes, such as retention ditches and/or live barriers laid out along the contour. Erosion and runoff control on the sides of each gully is an essential part of the rehabilitation process. These check dams of rooted poles are more robust and durable than stone dams in soils of sandy/ loamy texture. On moderate and steep slopes a combination of stem cutting and stone dams is recommended.

After two to three years the barriers should be pruned - yielding wood and fodder. Dead poles should be replaced and the dam widened if necessary.

In this case study the dams are constructed in a semi-arid region with erratic rainfall where gullies are common on agricultural land, be it cropland or grazing land. The land users are mainly peasant farmers, growing crops for subsistence on smallholdings, and living in very poor conditions. This system of gully rehabilitation is promoted by an NGO entitled ‘Asociación Tierra y Vida’ through farmerto-farmer (campesino a campesino) extension.

2.3 Photos of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

Country:

Nicaragua

Region/ State/ Province:

Santa Teresa, Paso de la Solera

Further specification of location:

Carazo, Nicaragua

Comments:

Total area covered by the SLM Technology is 5 km2.

Map

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2.6 Date of implementation

If precise year is not known, indicate approximate date:

• less than 10 years ago (recently)

2.7 Introduction of the Technology

Specify how the Technology was introduced:

• through projects/ external interventions

3.1 Main purpose(s) of the Technology

• reduce, prevent, restore land degradation
• reduce risk of disasters

3.2 Current land use type(s) where the Technology is applied

Cropland

• Annual cropping

Specify:

Longest growing period in days: 100, Longest growing period from month to month: May to August; Second longest growing period in days: 90, Second longest growing period from month to month: September to November

Grazing land

Comments:

Major land use problems (compiler’s opinion): There is a range of factors that limit agricultural production in the area: soil degradation, extensive gully formation on crop land, low soil fertility, lack of inputs for crop production, erratic precipitation. Also, lack of interest/knowledge and lack of resources hinder the implementation of SWC measures.

3.4 Water supply

Water supply for the land on which the Technology is applied:

• rainfed

3.5 SLM group to which the Technology belongs

• cross-slope measure

3.6 SLM measures comprising the Technology

vegetative measures

• V5: Others

structural measures

• S4: Level ditches, pits
• S5: Dams, pans, ponds

Comments:

Specification of other vegetative measures: stem cuttings; live barriers along contour (supp.)
Specification of other structural measures: check dams; retention ditches

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

• Wg: gully erosion/ gullying

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:

• restore/ rehabilitate severely degraded land

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

Stem cuttings planted in gullies to form living check dams: recently planted (left) and cuttings that have begun to take root and sprout, resulting in the gully becoming filled with trapped sediment (right).

Technical knowledge required for field staff / advisors: low
Technical knowledge required for land users: moderate
Main technical functions: control of concentrated runoff: retain / trap, levelling of land
Secondary technical functions: reduction of slope angle, reduction of slope length

Construction material (wood): jinocuebo (Simaroubaceaes bombacaceaes, and also jobo, tiguilote, pochote from the same family), j
Slope (which determines the spacing indicated above): 15%

Author:

Mats Gurtner

4.3 Establishment activities

4.4 Costs and inputs needed for establishment

Comments:

Duration of establishment phase: 2 month(s)

4.5 Maintenance/ recurrent activities

4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)

Comments:

Costs are calculated for a 100 m long, 2 m wide and 1 m deep gully with check dams every 4 m, on the basis of one gully per hectare.

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

The wood (for poles) belongs to the land users themselves, thus the ‘cost’ does not involve purchase.

5.1 Climate

5.2 Topography

5.3 Soils

5.6 Characteristics of land users applying the Technology

Indicate other relevant characteristics of the land users:

Off-farm income specification: temporary or permanent migration, particularly young people

5.7 Average area of land used by land users applying the Technology

5.8 Land ownership, land use rights, and water use rights

Land ownership:

• individual, not titled
• individual, titled

Land use rights:

• leased
• individual

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Income and costs

Socio-cultural impacts

Ecological impacts

Soil

6.2 Off-site impacts the Technology has shown

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?

6.5 Adoption of the Technology

• > 50%

Comments:

66% of land user families have adopted the Technology with external material support
30% of all farmers approached by the project (about 400 out of 1,200 land users) have built these check dams. Seeds, tools and credits were provided as incentives; the reasons for implementation included both the attraction of the incentives and perceived ecological benefits in terms of rehabilitation of degraded areas.

34% of land user families have adopted the Technology without any external material support

There is a strong trend towards spontaneous adoption of the Technology

6.7 Strengths/ advantages/ opportunities of the Technology

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

Gurdiel G . La construcción de diques. Tierra Fresca, Simas-Enlace, Managua. 1993.

Title, author, year, ISBN:

Guía Técnica de Conservación de Suelos y Agua. PASOLAC, Managua. 2000.

Title, author, year, ISBN:

LUPE . Manual Práctico de Manejo de Suelos en Laderas. Secretaría de Recursos Naturales, Tegucigalpa, Honduras. 1994.